Brake mechanism



June 1,1937. R. Mec. JoHNsToNE BRAKE MECHANISM Filed Aug. 23, 1955 3Sheets-Sheet l ATTORNEY June 1, 1937. R. Mac. JoHNsToNE 2,082,633

BRAKE MECHANISM Q v Filed Aug. 23, 1935 v Z- Sheets-Sheet 2 Jg- Z.

W ATTORNEY 3 Sheets-Sheet 5 R. MCC. JOHNSTONE BRAKE MECHANISM Filed Aug.25, 1955 June l, 1937.

Patented June 1, 1937 UNITED STATES PATENT OFFICE BRAKE MECHANISMApplication August 23, 1935, Serial No. 37,494

6 Claims.

'I'his invention relates to web roll supporting -means having brakemechanism for automatically controlling the tension of the web issuingtherefrom, and has for its main object and feature the provision of aneffective and simple brake and control mechanism capable of adjustmentas a unit with the web roll supporting means to center the web withrespect to a web pulling machine such as a carbon coating, printing orother machine.

Other objects and advantages will appear from the following description,taken in connectionv with the accompanying drawings, in which apreferred form of the invention is disclosed, and in which:

Fig. 1 is a side elevation of an unwinding' stand carrying a web roll offlexible material, and provided with a tension-controlled brake;

Fig. 2 is a plan view of Fig. 1 with the central.

portion of the web and rollers broken away;

Fig. 3 is a horizontal section through the brake substantially on theplane of line 3-3 of Fig. 1;

Fig. 4 is a fragmentary vertical section substantially on thplane ofline 4-4 of Fig. 1; and

Fig. 5 is a fragmentary view showing a modified form of threading theflexible connection supporting the weight of the tension controllingmeans.

The specific arrangement shown in the drawings discloses the inventionapplied to an unwinding stand carrying a roll of flexible material fromwhich a web is drawn for feeding a webpulling machine such as a printingpress, coating machine or the like, indicated generally at X. Theunwinding stand frame I0 is provided with the mill roll shaft `I adapted*to receive the roll of paper I2; and in accordance with usual practiceshaft Il may be continuous or may be 1nsections and carrying the usualchucks on apposite sides of roll I2.

One end of shaft I extends beyond frame I0 and over brake stand I3,which is provided with guide ways I4 in which brake base I5 is slidablymounted for transverse adjustment in line with mill roll shaft I.'I'he'transverse motion is imparted in any desirable manner, as by screwI6 (Fig. I) 'journaled in brake stand I3 and having a threadedengagement vwith lugs-Ifprojecting downwardly from brake base I5. ScrewI6 may be turned in either means. asbylgear train I8 and reversiblemotor I9 for purposes hereinafter indicated.

Upon brake base I5 there is mounted afvariable pressure brake adaptedfor accurate adjustment to regulate the web tension. The brake includesdirection by any desiredv a plurality of elements. at least one of whichis mounted to rotate with the roll-supporting means, and at least one ofwhich is mounted independently thereof. Said elements may comprise arotary member arranged for connection 5 with and rotation by mill rollshaft and nonrotating members frictionally engaging the rotatable memberwith adjustable pressure. The specinc-form illustrated includes a fixedbrake shoe 28 mounted rigidly on base I5 and carrying hori- 10 zontalguide rods 2| (Fig. 3) bolted to shoe 20. Sliding brake shoe 22 isslidably mounted on guide rods 2|.

Brake shaft 23` is rotatably mounted in ball bearings 24 in a suitablebore through xed brake shoe 20 in alignment with mill roll shaft and isprovided with a suitable coupling engaging the end of shaft Il', adaptedto transmit both rotary and axial movement. A suitable arrangementincludes hollow driving head 25 on the outer 20 end of brake shaft 23,provided with bayonet slot 26 engaged by pin 2'I on the end of mill rollshaft I I (Fig. 2). The rotary brake disk is mounted on`the inner, endof brake shaft 23 between brake shoes 20 and 22 and preferably ismovable axially I, of brake shaft 23 to provideevenpressure on bothshoes regardless of the position of the shoes. A convenient arrangementis illustrated, including a driving plate 28 (Fig. 3) o n the inner endof brake shaft 23, engaging annular steel brake disk 29 provided withsuitable brake facing 3U on both sides, positioned for frictionalengagement with cooperating surfaces on brake shoes 20 and 22. Disk 29is axially slidable but-non-rotatable on driving plate 28, as bygivingplate 28 a hex- .,7 agonal or other non-circular peripheral contour,with a close buttransversely sliding fit in a regis-l tering opening inthe center of brake disk 29. Coil springs 3| on guide rods 2| betweenbrake shoes 20 and 22 tend to keep the shoes apart and 40 out ofengagement with brake disk 29. The brake shoes 28 and 22 may bewater-cooled, and are shown with water Jackets 32 connected at thebottom by flexible pipe 33 and at the top to inlet and outlet lines 34.

A suitable `arrangement is provided for gradual adjustment of the brakepressure, preferably by rotation of a threaded member. In the formshown, pressure screw 35 mounted on sliding brake shoe-22 is threadedthrough pressure sleeve 50 36 rotatably mounted by flange 31 and thrustball bearings 31a in a suitable bore in` yoke 38 mounted on `guide rods2|. Small'sprocket 39 is rotated through chain 4|) by largesprocket 4|rotatably mounted on the outer end of a guide 55 rod 2l. Yoke 38 andsliding brake shoe 22 are spaced so that when shoe 22 is fullyretracted, brake disk 29 can be slid from driving plate 28 and withdrawnfor repair or replacement.

The brake is operated by a suitable device responsive to variations inweb tension. This preferably includes a roller held against the webunder relatively xed pressure and shifted transversely to the web pathby variations in the web tension. In the illustrated embodiment web 42runs from the mill roll I2 over guide roller 43, thence downwardly undertension roller 44 and up over guide roller 45 to a processing machine(not shown), forming a downwardly' extending loop of web in whichtension roller 44 rests.

Tension roller 44 revolves freely on tension roller shaft 46, and isprovided with meansfor restricting its vertical movement to a fixed pathand for maintaining it in horizontal position, transversely aligned withthe web. This may include vertical guideways 41 in which shaft 46isslidable at either side of roller 44, and vertical racks 48 mounted onthe unwinding stand frame f I0 positioned to maintain engagement withpinions 49 xed on tension roller shaft 46 adjacent guideways 41 andsevering to keep tension roller 44 in horizontal alignment when shaft 46is supported and moved by engagement with one end only, as by thecontrol mechanism to be described.

An arrangement is provided for regulating the brake pressure inaccordance with vertical movements of tension roller 44. In theembodiment shown, tension roller shaft 46 passes between the paralleljaws of a fork 50 on the end of tension lever arm 5I fixed at its otherend to rock shaft 52 journaled in the unwinding stand frame IU and inbracket 53 on brake stand I3. Rocker arm 54 is fixed to the outer end ofrock shaft 52, forming with tension lever arm 5I a bell crank lever. Theupper end of rocker arm 54 is oonnected through universal joint 55 withlink 56, the other end of which is connected to the large sprocket 4I,so that vertical movements of fork 50 will oscillate sprocket 4I andvary the brake pressure.

The connection of link 56 with the brake mechanism is preferablydetachable and adjustable to permit regulation of the effect ofmovements of tension roller 44. Such connection may comprise aconnecting arm 51 pivoted at its lower end on the end of the guide rod2i carrying large sprocket 4I` Arm 51 is adjustably connected to largesprocket 4| by spring-actuated plunger 58 (Fig. 4) entering one of theseries of socket openingsy59 concentrically arranged in sprocket 4I.Link 56 is adjustably connected to the upper .part of arm 51 by auniversal joint, as by pivoting the end of link 56 in a fork 60 bearingagainst the face of arm 51 and having a pivot stud 6I passing throughone of a vertical series of openings 62 in connecting arm 51 androtatably retained therein as by nut 63.

The downward pressure on tension roller 44 should be such that when web42 is under the desired tension, roller y44 will be in an intermediateposition as shown in Fig. 1. This can be attained to a certain extent byproperly designing the weight of tension roller 44 and connected parts,and the length and weight of tension lever arm 5I. It is desirablehowever to provide means for adjusting such downward pressure on roller44; and our arrangement for this purpose is disclosed, adapted either toadd or subtract an adjustable amount of pressure applied to said roller44.

'Ihis is accomplished by mounting on opposite sides of unwinding standframe I0, and in line with the .ends of tension roller shaft 46, lowerpulleys 64 below the ends of shaft 46, and upper pulleys 65 above theends of shaft 46. Cables 66 may run from the ends of shaft 46 downwardlyaround pulleys 64 as in Fig. 1, thence upwardly over pulleys 65,carrying adjustable sectional weights 61 at their ends, as shown in Fig.1 in full lines, thereby adding the pull of weights 61 to the downwardpressure on tension roller 44; or cables 66 may run from the ends ofshaft 46 directly up over pulleys 65 as shown in Fig. 5, therebysubtracting the pull of weights 61 from the downward pressure on roller44.

The method of operation will in general be evident from the detaileddescription. When the mill roll I2 is placed on the unwinding stand Illdriving head 25 is in retracted position with bayonet slot 26 inalignment with pin 21, and motor I9 is operated to shift the entirebrake unit toward roll I2, positioning pin 21 in slot 26. When web 42 isthreaded over rollers 44 and 45 and through the processing machine, thestart of said machine applies traction to the web; but as the tensionroller 44 is in lowermost position the brake is set to prevent rotationof mill roll I2.

Tension on the web increases until it is sufcient to lift tension roller44, rotating large sprocket 4I to the right and retracting sliding brakeshoe 22 gradually until the increasing tension on web 42 overcomes thedecreasing resistance of the brake, and mill roll I2 starts to rotate,feeding web 42 to the processing apparatus. When the downward pressureof tension roller 44 is set for a predetermined tension on web 42, as byadjusting weight 61, such tension will be automatically maintained; forany decrease in tension will cause the tension roller 44 to drop,increasing brake pressure and building up the tension, while any rise intension above the optimum will liftroller 44,- decrease brake pressureand reduce the tension.

This method of operation automatically takesI care of the necessarygradual reduction in brake pressure as the diameter of roll I2 decreasesand the speed of rotation increases and does not depend directly onoperating -conditions such as the rate of roll rotation, the number ofrevolutions made, or the roll diameter. It is moreover responsive to anychanges in conditions, either in the feed roll or the processingmachine, that might aiect the web tension. If the web should break, thebrake would immediately be applied and stop the roll promptly, withoutrequiring any resetting or adjustment when starting up after a break.

The arrangement shown is adjustable for several purposes. By retractingplunger 58, tensionroller 44 is disconnectedfrom the brake, which may beadjusted by rotating manually the large sprocket 4I, either forretracting sliding brake shoe 22 so that brake disk 29 may be slid offdriving plate 28 and removed for replacement or repair, or t0 adjust theposition of sliding brake shoe 22 so that the brake pressure will besuitable to maintain tension roller 44 in an intermediate position whenrunning at the desired tension. Such brake adjustment may be needed tocompensate for wear,- changes in tension or for other reasons; and whenthe brake is properly set, plunger 58 is set in the proper opening 59 tolocate roller 44 appropriately under running conditions. The

aoeacas braking eil'ect of movements of roller Il can also be adjustedby locating pivot stud 8| in the appropriate opening 62.

The universal joints at the ends of link ss permit transverse movementof the brake on stand I3, either for engaging and disengaging drivinghead 25 with the mill roll shaft II, or for adjusting the lateralposition of mill roll I2 while in operation, as the bayonet slot 26engages pin 21 in operation so thaty transverse movements of the brakein either direction are transmitted to the mill roll, and therefore saidroll can be transversely aligned during unwinding by operation of motorI9.

While the invention has been described as applied to paper unwindingapparatus, numerous features are applicable to othertypes of apparatus.In the illustrated embodiment web pressure is applied by gravity, andthe expressions horizontal and vertical" have been used; but while suchan arrangement has special advantages, other arrangements. are possible,and the terms are used by way of description and not oi' limitation. s

I claim:

l. Apparatus for controlling brake action in-v cluding a brake providedwith rotary means for varying the brake pressure, and operating meanshaving a concentrically and radially adjustable connection with saidrotary means.

2. Apparatus for controlling brake action including a brake, a controlmember under pressure, operating connections between the control memberand the brake, and means for varying the pressure on said memberincluding a pulley below the member, a pulley above the member,a exiblecable connected to the member and an adjustable weight mounted on saidcable, the construction and arrangement being such that thegravitational pull of said weight is added to' the pressure on saidmember when the cable is passed under the lower pulley and then over theupper pulley, and is subtracted from said pressure when the cable ispassed directly over the upper pulley.

3. Braking apparatus including a plurality of complementary brakeelements, rotatable means for regulating the operative engagement ofsaid elements, an oscillating control member, means for rotating saidrotatable member at a predetermined rate in response to a given movementof said control member, and means for varying said rate.

4. Web supply means including: rotatable supporting means to carry aroll of web supply the end of which is threaded into a web-pullingmachine; a plurality of complementary brake elements carriedconcentrically of the axis of the web roll, at least one o1' which ismounted to rotate with the supporting means and at le`ast one of whichis mounted independently thereof and is movable, to vary theoperatlveengagement of said brake elements, in a direction lengthwise of the axisof said supporting means; rotatable means, coincidental with the axis ofsaid supporting means to regulate the operative engagement of said brakeelements; an oscillating control member arranged eccentric with respectto the axis of said supporting'ineans; transmission means between theoscillating control member and said rotatable means; a base member,adjustable in a direction lengthwise of the axis of the supportingmeans, carrying the supporting means, the brake elements, the rotatablemeans, the oscillating control member and the transmission means; aoating roller, mounted independently of the base member, to engage aloop in the web and thereby to respond to variations in tension ot theweb; and adjustable connections between the oating roller and theoscillating control member.

5. Web supply means including: rotatable supporting means to carry arollof web supply the end of which is threaded into a web-pulling ma chine;a plurality of complementary brake elements carried concentrically ofthe axis of the web roll, at least one of which is mounted to rotatewith the supporting means and at least one of which is mountedindependently thereof and is movable, to vary the operative engagementof said brake elements, in a direction lengthwise of the axis of saidsupporting means; rotatable means, coincidental with the axis of saidsupporting means to regulate the operative engagement of Asaid brakeelements; an oscillating control member arranged eccentric with respectto the axis of said supporting means; transmission means between theoscillating control member and said rotatable means; a base member,adjustable in a direction lengthwise of the axis of the supportingmeans, carrying the supporting means, the brake elements, the rotatablemeans, the oscillating control member and the transmission means; afloating roller; mounted independently of the base member, to engage aloop in the web and thereby to respond to variations in tension of theweb; and connections, including a universal joint; between the iioatingroller and the oscillating control member. l

6. Web supply means including: rotatable supporting means to carrya-rol1 of web supply the end of which is threaded into a web-pullingmachine; a plurality of complementary brake elements carriedconcentrically of the axis of the web roll, at least one of which ismounted to rotate with the supporting means and at least one of which ismounted independently thereof and is movable, to vary the operativeengagement of said brake elements, in a direction lengthwise of the axisof said supporting means; rotatable means, coincidental with the axis ofsaid supporting means to regulate the operative engagement of said brakeelements an oscillating control member arranged eccentric with respectto the axis of said supporting means; transmission means between theoscillating control member and said rotatable means; a base member,adjustable in a direction lengthwise of the axis of the supportingmeans, carrying the supporting means, the brake elements, the rotatablemeans, the oscillating control member' and the transmission means; afloating roller, lmounted independently oi' the base member, to engage aloop in the web and thereby to respond to varia-y

